baber/WOPTO huggingface dataset:
Patent BR-0306422-A (BR)
Title: Rotor eólico tubular com sistema de contrapeso
Inventor: RABELO LUCIANO DUTRA
IPC: F03D3/06
Filed: 2003-12-16
Abstract: "ROTOR EóLICO TUBULAR COM SISTEMA DE CONTRAPESO". Utilizado para captar força eólica através de um eixo elevado, com projeção vertical, equipado com 18 hélices curvas, dispostas em espiral, com 3 fileiras horizontais e 6 fileiras verticais, (fig. 1) com diferenças de peso entre as hélices (fig. 2) de modo a provocar deslocamentos no centro de gravidade do eixo, em conseq³ência da aplicação da forca do vento, de forma alternada, em hélices de diferentes pesos, dispostos em posição simétrica e diametralmente opostas. O próprio eixo elevado permite a obtenção da altura necessária ao funcionamento do rotor, que pode ser instalado em uma estrutura mais baixa, com menor custo de instalação e maior facilidade de acesso ao gerador (5 da fig.1). A transmissão de força é efetuada para um gerador localizado na extremidade inferior do eixo. Além da pressão normal do vento sobre o conjunto de hélices, a alternância da aplicação de força nas hélices de maior e de menor peso, faz com que o centro de gravidade do eixo se desloque ao longo do formato cilíndrico do mesmo, provocando uma rotação em parafuso, o que facilita a quebra da resistência inercial. O fato de o rotor ser equipado com hélices curtas produz um menor efeito de alavancagem das hélices sobre o eixo, o que é compensado pelo maior número de hélices e pelo efeito causado pelos contrapesos distribuídos nas hélices, que 'arremessam' o centro de gravidade no sentido direcional do movimento, criando dois vetores adicionais de força de aplicação tangencial intensificada, nos pontos do eixo onde há maior concentração de peso. Por ter um formato tubular (fig. 1), este rotor funciona com vento em qualquer direção, sem haver necessidade de reposicionamento do mesmo, em função da mudança de direção do vento. E por ter um formato mais compactado, com hélices curtas, é menor a área de rotação das hélices, o que reduz o risco de acidente e permite a instalação do rotor em pequenos espaços, tais como lajes superiores de prédios e residências, favorecendo o conceito de geração distribuída.
Patent BR-0308168-A (BR)
Title: Método para preparar oxi-hidróxido de nìquel, bateria, métodos para fabricar bateria, e para diminuir a perda de capacidade em bateria de oxi-hidróxido de nìquel
Inventor: CHRISTIAN PAUL A
IPC: H01M6/06
Filed: 2003-03-04
Abstract: "MéTODO PARA PREPARAR OXI-HIDRóXIDO DE NìQUEL, BATERIA, MéTODOS PARA FABRICAR BATERIA, E PARA DIMINUIR A PERDA DE CAPACIDADE EM BATERIA DE OXI-HIDRóXIDO DE NìQUEL". Oxi-hidróxido de níquel pode ser preparado pela exposição de uma mistura de hidróxido de níquel e um sal hidróxido ao ozónio. O oxi-hidróxido de níquel é apropriado para uso no catodo de uma bateria.
Patent BR-0308980-A (BR)
Inventor: JOGER HELMUT
IPC: E01B11/00
Filed: 2003-04-04
Abstract: In a transition rail ( 1 ) for the connection of rails having different rail cross sections ( 2, 3 ), the transition rail ( 1 ) comprises two transition zones (a,c), wherein in a first transition zone (c) the larger-height cross-sectional profile is reshaped to transition into a smaller profile height and in the following, second transition zone (a) the rail foot is worked to match the new profile of the consecutive rail foot. The method for producing the transition rail is characterized in that the transition rail is at first heated and introduced into a press mold, whereupon the rail is reshaped in the web region and pressed in the direction of the profile height, and that the rail foot is mechanically worked following complete reshaping.
Patent BR-0314214-A (BR)
Title: Partìcula para transporte de membrana magneticamente induzida
Inventor: FREDRIKSSON SARAH
IPC: C12N15/87
Filed: 2003-09-11
Abstract: "PARTìCULA PARA TRANSPORTE DE MEMBRANA MAGNETICAMENTE INDUZIDA". A presente invenção refere-se a partículas, para uso no transporte de substâncias através de membranas biológicas, a partícula sendo caracterizada pelo fato de que ela contém pelo menos um material magneticamente induzido e pelo menos uma molécula bifuncional com pelo menos um local de ligação para a dita membrana biológica. Além do mais, a invenção refere-se à produção das mesmas partículas e suas aplicações.
Patent BR-1100527-A (BR)
Inventor: KUEFNER-MUEHL ULRIKE DR
IPC: A61P9/00
Filed: 1997-05-13
Abstract: Xanthines of formula (I) and their optical isomers and acid-addn. salts are new: R1 = 1-6C alkyl, 3-4C alkenyl or 3-4C alkynyl; R2 = 1-6C alkyl, 3-4C alkenyl, 3-4C alkynyl or opt. substd. benzyl; R3 = (a) C-bonded satd. or unsatd. 5- to 7-membered heterocyclyl contg. one or more O and/or S atoms, opt. substd. by 1-6C alkyl, oxo, CHO, CH2OR4, CH2OR7, COOR4 or CONR5R6; where furyl and thienyl gps. are opt. also substd. and tetrahydrofuryl gps. are opt. also substd; (b) 4-8C cycloalkenyl opt. substd. by 2-4C alkenyl; (c) a 4-8C cycloalkanone or cycloalkanol gp. opt. alpha-substd. by 2-6C alkenyl, 2-6C alkynyl, opt. substd. benzyl, CH2OR4, CH2COOR7 or CH2CH2CN; (d) 3-8C cycloalkyl opt. substd. by 1-6C alkyl, =CH2, =NNHAr, =NNHR, =NOH, OCONHAr, OCONHR, OR4, OR7, (CH2)xCOOR4, (CH2)xNR4R4, (CH2)xCONR5R6, (CH2)xOR4, (CH2)xOR7 or =CHA; (e) 3-8C cycloalkyl gem-substd. by OH and 1-6C alkyl, vinyl, allyl or opt. substd. phenyl or (1-4C alkyl)phenyl; (f) 3-8C cycloalkyl gem-substd. by ORa and ORb, or (g) 3,4-methylenedioxyphenyl, 3,4-ethylenedioxyphenyl, 2-fluorenyl, 9-fluorenyl or a bicyclic gp., e.g. of formula (i)-(iii). Ar = opt. substd. aryl; R = 1-6C alkyl, x = 0-4; A = COOR4, CN, CONR5,R6, CH=CHCOOR4, CH=CHCONR5R6, CH2OR4 or CH2OR7; Ra and Rb = 1-4C alkyl, or Ra+Rb = 2-3C alkylene opt. substd. by 1 or 2 of 1-5C alkyl, 2-6C alkoxycarbonyl and 1-5C hydroxyalkyl; R4 = H, 1-13C alkyl, 3-13C alkenyl, propargyl, trityl or opt. substd. 3-6C cycloalkyl or benzyl; R5 = H, 1-6C alkyl or opt. substd. 3-6C cycloalkyl; R6 = H, 1-6C alkyl, opt. substd. benzyl, (CH2)nNR5R5, ((CH2)nO(CH2)mO)k(CH2)nNR5R5, (CH2)nQ(CH2)nNR5R5, or C-bonded piperidinyl opt. substd. ; or NR5R6 is a 5- to 7-membered ring opt. contg. another heteroatom and opt. substd. ; n = 2-8; m = 2-6; k = 0 or 1; Q = piperazine-1,4-diyl opt. substd. ; R7 = acyl derived from a natural amino acid, 2-14C alkanoyl, methyloxyacetyl, camphanoyl, abietoyl, 4-aminobutyryl, opt. substd. benzoyl or COB1; B1 = opt. substd.
Patent BR-8403439-A (BR)
Inventor: STAHLHOFEN PAUL
IPC: G03C1/52
Filed: 1984-07-10
Abstract: A process for producing negative relief copies is disclosed in which a light-sensitive material, comprising (1) a light-sensitive ester or amide of a 1,2-quinone-diazide-sulfonic acid or of a 1,2-quinone-diazide-carboxylic acid and (2) a hexamethylol melamine ether is imagewise exposed, thereafter heated, and, after cooling, exposed again without an original, and subsequently developed by means of an aqueous-alkaline developer. The disclosed process permits the production of negative copies with the aid of a material which yields positive copies when it is processed in a conventional manner.
Patent BR-8601211-A (BR)
Inventor: PILKINGTON DONOVAN
IPC: B62K3/10
Filed: 1986-03-07
Abstract: This invention relates to a bicycle. The bicycle includes a frame joining the front and rear wheels where the frame comprises a leaf spring suspension which enables the front and rear wheels to resiliently pivot relative to one another. The saddle and pedal mechanism are attached to the suspension.
Patent BR-8807723-A (BR)
Inventor: WARD JONATHAN
IPC: B26B/
Filed: 1988-09-30
Abstract: PCT No. PCT/GB88/00805 Sec. 371 Date Apr. 23, 1990 Sec. 102(e) Date Apr. 23, 1990 PCT Filed Sep. 30, 1988 PCT Pub. No. WO89/02812 PCT Pub. Date Apr. 6, 1989.A cutting guide for use in making a cut in a carpet comprises an elongate base including a substantially flat upper surface portion and a channel which extends along the base. The inner side walls of the channel are at an oblique angle relative to the upper surface portion so that when the guide is placed underneath a carpet and a knife drawn along the channel in contact with a side wall, the cut edge thereby produced in the carpet is at an oblique angle to the plane of the carpet. When two such edges of different portions of carpet are abutted together, a tidy unobtrusive seam is produced.
Patent BR-8903945-A (BR)
Inventor: LOEHER HEINZ-JOSEF
IPC: C07D475/04
Filed: 1989-08-04
Abstract: Sulphonyl ureas substituted by heterocycles, of the formula 
<IMAGE>
 in which A denotes a C1-C10-hydrocarbon radical, R<1> denotes saturated or unsaturated alkyl or cycloalkyl which can be substituted by halogen or radicals from the group comprising saturated or unsaturated alkoxy or alkylthio, alkylsulphinyl, alkylsulphonyl, cycloalkyl, a radical of a three- to six-membered saturated heterocycle having an oxygen atom in the ring, furyl and phenyl, optionally substituted by halogen, alkyl, alkoxy, CF3, alkoxycarbonyl and/or nitro, or R<1> denotes phenyl, optionally substituted by halogen, alkyl, alkoxy, CF3, alkoxycarbonyl or nitro, or R<1> denotes a radical of the formula -CO-R<5>, -CHR<6>-COOR<7>, -CHR<6>-CH2-COOR<7> or -CH2-CHR<6>-COOR<7>, where in the formulae R<5> stands for alkyl, R<6> stands for hydrogen, alkyl, phenyl or benzyl and R<7> stands for alkyl, phenyl or benzyl, Y denotes S or SO2, R<2> denotes H, saturated or unsaturated alkyl, optionally substituted by halogen, saturated or unsaturated alkoxy, alkylthio, alkylsulphinyl, alkylsulphonyl, alkoxycarbonyl, phenoxycarbonyl, benzyloxycarbonyl or phenyl; or C3-C8-cycloalkyl, optionally substituted by halogen, alkoxy or alkylthio; or cycloalkenyl, cyclopropylmethyl, epoxypropyl, furfuryl, tetrahydrofurfuryl, phenoxy-C1-C6-alkyl, phenyl, or phenyl or phenoxyalkyl substituted in the phenyl ring by halogen, alkyl, alkoxy or nitro, R<3> denotes H, saturated or unsaturated alkyl, or C1-C4-alkoxy, R<4> denotes a radical of the formula 
<IMAGE>
 R<8> and R<9> denote H, halogen, alkyl, alkoxy, alkylthio or the latter 3 radicals substituted by halogen, alkoxy or alkylthio; or NR<1><4>R<1><5>, cycloalkyl, -OCHR<1><5>COOR<1><7>, unsaturated alkyl or alkoxy, R<1><0> denotes H or alkyl: R<1><1> denotes alkyl, -CHF2 or -CH2CF3; R<1><2> denotes H, alkyl, alkoxy or halogen; R<1><3> denotes H, alkyl, CHF2 or CH2CF3; R<1><4> and R<1><5> denote H or saturated or unsaturated alkyl; R<1><6> and R<1><7> denote H or alkyl; E denotes CH or N; G denotes CH2 or O and Z denotes O or S, and their salts have herbicidal and plant growth regulatory properties in mono- and dicotyledon plants.
Patent BR-8907082-A (BR)
Inventor: SERRES ALAIN
IPC: B04B1/00
Filed: 1989-09-12
Abstract: PCT No. PCT/FR89/00458 Sec. 371 Date Apr. 30, 1990 Sec. 102(e) Date Apr. 30, 1990 PCT Filed Sep. 12, 1989 PCT Pub. No. WO90/02839 PCT Pub. Date Mar. 22, 1990.A device for separating particles in a liquid in which a paper suspension is to be cleaned and supplied to a chamber of revolution (1) rotating about an axis (2). Movable deviators (7, 8) precede the fixed outlets (9, 10) to intercept most of the through-put of the suspension in the region of the periphery of the chamber (1), then deviate it towards the longitudinal axis of rotation (2) so as to recover most of the kinetic energy of rotation. The outlets (7, 8, 9, 10) are situated at the opposite end to that of chamber (1) from the supply (5, 6) and are arranged at the periphery of this chamber (1). A diabolo-shaped central body of revolution (11) is arranged inside the chamber, along the longitudinal axis of rotation (2) for rotation about its axis and with a radial run-off (12) in the vicinity of its smallest cross-section connected to an axial outlet duct (13).
Patent BR-9005288-A (BR)
Inventor: LANG GERARD
IPC: A61K8/00
Filed: 1990-10-19
Abstract: Oxidation dyeing composition intended for use for dyeing keratinous fibres, especially human keratinous fibres, and in particular the hair, which contains, in a solvent medium suitable for dyeing these fibres, at least one para oxidation dye precursor or at least one ortho oxidation dye precursor and at least one heterocyclic coupler corresponding to the formula (I): <IMAGE>  in which:   R1 and R3, which may be identical or different, denote a hydrogen atom or a C1-C4 alkyl group; R2 denotes a hydrogen atom, a C1-C4 alkyl group, a carboxyl group or an alkoxycarbonyl group; at least one of the radicals R2 or R3 denoting hydrogen; R4 denotes a hydrogen atom or a C1-C4 alkyl or C1-C4 hydroxyalkyl or C2-C4 polyhydroxyalkyl group;   the group NHR4 occupying positions 4, 6 or 7 of the benzene ring, as well as their salts.
Patent BR-9006191-A (BR)
Inventor: MORELLO PETER S
IPC: B41J35/14
Filed: 1990-12-06
Abstract: Sales records comprising alphanumeric characters that are resistant to counterfeiting are generated by printing different parts of at least some of the characters making up the record in a plurality of colors. An apparatus for printing such sales records comprises a ribbon split in the direction of its advance into contiguous portions carrying different color inks thereon and means for advancing the ribbon automatically during use of the apparatus.
Patent BR-9100641-A (BR)
Inventor: CHEN SHIN CHIANG
IPC: G01P15/08
Filed: 1991-02-18
Abstract: A vehicle brake warning device for use in a vehicle (5) with a brake pedal (51) includes an inertial transducer (1, 6) which produces different electrical signals in response to the magnitude of inertial force experienced during braking, a control circuitry (4, 4') receiving electrical signals from the inertial transducer (1, 6) and having an output dependent upon the received signal, and a warning device (3) activated by the output of the control circuitry (4, 4'). Whenever the brake pedal (51) is actuated to reduce the speed of the vehicle (5), the inertial transducer (1, 6) experiences an inertial force whose magnitude depends upon the speed of the vehicle (5). The inertial transducer (1, 6) sends out an appropriate signal to the control circuitry (4, 4'), which signal corresponds to and is dependent upon the magnitude of the inertial force. The control circuitry (4, 4') activates the warning device (3) to send out a warning signal which varies depending upon the magnitude of the inertial force.
Patent BR-9105927-A (BR)
Inventor: WEINGARTNER RUDOLF
IPC: B60N2/90
Filed: 1991-01-10
Abstract: The invention describes a seat, in particular for vehicles, with an upholstered element made of foamed plastic which has a support element (7) consisting of an open-cell, elastic plastics foam and a flame-resistant covering material (15) which are connected to one another, in particular bonded at certain points. A covering layer (19) made of a woven cloth or knitted fabric or nonwoven is attached, in particular bonded, onto an underside of the supporting element (7) lying opposite the seat faces (14). <IMAGE>
Patent BR-9206648-A (BR)
Inventor: TIMMONS ALBAN
IPC: B01D43/00
Filed: 1992-10-16
Abstract: PCT No. PCT/GB92/01904 Sec. 371 Date Apr. 18, 1994 Sec. 102(e) Date Apr. 18, 1994 PCT Filed Oct. 16, 1992 PCT Pub. No. WO93/07948 PCT Pub. Date Apr. 29, 1993.A separator for separating contaminants from a base liquid. The separator includes a roof arrangement, part of which extends downwardly and radially inwardly into the liquid in the separator. The roof arrangement is generally in inverted conical form. The decontaminated liquid flows from the separator through a flow modifying member which dampens any circulating flows in the liquid, and flows upwardly out of the separator to a reservoir defined by the inverted conical roof arrangement. The arrangement also includes structure for releasing gases from the volumes beneath the roof arrangement, thereby maintaining the whole of the roof arrangement in contact with the liquid to assist in reducing circulating flow in the liquid on the upper regions of the separator vessel.
Patent BR-9206744-A (BR)
Inventor: BELL PETER WILLIAM
IPC: A47G27/02
Filed: 1992-11-10
Abstract: A floor covering, such as a carpet or carpet tile, which comprises a primary backing sheet having a fibrous face wear surface and back surface and first and second backing layers and with a low density, resilient, non-elastomeric, closed cell polymeric foam layer, such as a thermoset, cross-linked polyethylene foam layer, positioned between and bonded to the first and second backing layers, optionally with a secondary backing layer bonded to the secondary bitumen backing layer. A method of producing a floor covering, such as a carpet tile, which comprises providing a primary backing sheet having a fibrous face wear surface and a back surface and bonding a first bitumen backing layer onto the primary backing sheet, bonding a low density, thermoset, polymeric foam layer to the first bitumen backing layer through a glass tissue to protect the polymeric foam layer and stabilize the composite, and bonding a second bitumen backing layer onto the polymeric foam layer. The second bitumen layer being beyond to a non-woven base wets through a glass tissue to protect the subfloor and stabilize the composite.
Patent BR-9300726-A (BR)
Inventor: JANCZAK ANDRZEJ
IPC: H01R4/24
Filed: 1993-03-03
Abstract: The invention relates to a cutting and clamping terminal element for contacting electrical conductors, in particular for cable cores of the telecommunication technology, comprising a U-shaped section piece of a U-shaped cross-section and having a cutting and clamping contact. In order to provide a cutting and clamping terminal element (1) by means of which a plurality of parallel electrical conductors (6) can be terminated and accurately positioned and guided, the U-shaped section piece (2) is adapted with one or several central webs (3), which are cut free from the bottom portion (7) and are upwardly bent off. Thereby one or more contact positions 9 are obtained for the electrical conductors (6).
Patent BR-9306215-A (BR)
Inventor: DINE JOHN E VAN
IPC: G02F1/15
Filed: 1993-04-12
Abstract: Electrochromic devices applied to a substrate are disclosed, including an electrochromic electrode layer, a counterelectrode layer, and an ion-conducting layer sandwiched between those two layers and electrically isolating them from each other, in which the ion-conducting layer is substantially uniform across the substrate and comprises an inorganic superstructure with associated organic material and with a microstructure which facilitates the transfer of ions. Methods for producing these devices are also disclosed, including depositing the ion-conducting layer on the substrate in the form of a solution, and effecting gelation of that solution.
Patent BR-9404925-A (BR)
Inventor: HABERSTROH JAMES A
IPC: B65B13/22
Filed: 1994-12-09
Abstract: An apparatus (10) for feeding and tensioning a strap (12) in a power strapping machine comprises a strap feeding mechanism (30), a strap tensioning mechanism (40), and a pivoting roller carriage (50) pivoted by a feeding and tensioning cam (70). The pivoting roller carriage (50) is first pivoted in one direction to move feed rollers (32, 34) together to engage a portion of a strap (12) and feed the strap (12) toward a strap application assembly where the strap is formed in a loop about an object or group of objects. The strap feeding and tensioning mechanism (10) actuates a first gripper (not shown) that secures an end of the strap in the strap application assembly. The pivoting roller carriage (50) then is pivoted to the opposite direction to move tension rollers (42, 44) together to engage a portion of the strap (12) and apply a tension to the looped strap. The strap feeding and tensioning apparatus (10) also actuates a second gripper (not shown) that secures the tensioned strap in a closed loop about the package so that the strap application assembly may form a strap joint sealing the strap in the closed loop. In the event that the strap (12) is not properly engaged by the first gripper, the strap will be fully retracted from the strap application assembly by the strap tensioning mechanism and the strap will be directed into a strap stretch-out housing (21) where it will remain until the strap feeding mechanism (30) again engages a portion of the strap (12) and re-feeds the strap toward the strap application assembly. The weight and position of the strap disposed in the strap stretch-out housing (21) prevents the strap from withdrawing entirely from the strap feeding mechanism (30) thereby ensuring that the strap feeding mechanism (30) will engage and re-feed the strap (12) to the strap application assembly automatically.
Patent BR-9503786-A (BR)
Inventor: REED LARRY E
IPC: C01B33/02
Filed: 1995-08-24
Abstract: For a given percentage decomposition, the decomposition temperature of an organosilicon compound is reduced by admixing with the organosilicon compound a decomposition promoting organotin compound. The amount of decomposition promoting organotin compound admixed with the organosilicon compound is sufficient to effectively lower the decomposition temperature of the organosilicon required for a given percentage decomposition. <MATH>
Patent BR-9506297-A (BR)
Inventor: HARRIS RANDALL LEE
IPC: B65D71/54
Filed: 1995-08-15
Abstract: A basket-style carrier which exposes major portions of packaged articles to view. Short inwardly tapered side panels are connected by integral flexible bands which encircle the end articles in the carrier. A handle may connect opposite flexible bands or may be incorporated in a handle panel extending up through an opening in the bottom panel of the carrier. A transverse base panel connected to the handle panel contacts the bottom panel in face-to-face relationship.
Patent BR-9510526-A (BR)
Inventor: FRIED HERBERT ELLIOTT
IPC: C08G59/12
Filed: 1995-12-18
Abstract: A novel epoxy-functional polyether composition is produced by reacting a carboxylic acid having formula (VI), wherein Q is A or B, X and Y are independently a hydrogen, methyl or ethyl group with the provision that if X is methyl or ethyl, Y is hydrogen or if Y is methyl or ethyl, X is hydrogen, and m+n+o is a positive real number from 1 to 450 and an epoxy resin having a functionality of at least 1.5 epoxide group per molecule.
Patent BR-9510647-A (BR)
Title: Inalador de medicamento.
Inventor: SLUTSKY ARTHUR
IPC: A24F40/00
Filed: 1995-10-03
Abstract: <B>INALADOR DE MEDICAMENTO<D>. Processo de distribuir uma dosagem predeterminada de formulação de nicotina através dos alvéolos e pequenas vias respiratórias do pulão para dentro da corrente sang³ínea de um paciente utiliza um inalador portátil contendo a formulação de nicotina. O inalador protátil pode ser usado como um substituto para tabaco (cigarro). Em uma modalidade, são descritas cápsulas de doses individuais para um inalador de pó portátil e sua fabricação.
Patent BR-9705832-A (BR)
Title: Dispositivo para proteger a junção de terminais decabos
Inventor: CLAVERIE BEATRICE
IPC: H02G15/192
Filed: 1997-11-24
Abstract: "DISPOSITIVO PARA PROTEGER A JUNçãO DE TERMINAISDE CABOS". A presente invenção refere-se um dispositivo protetorde conexões habilitando extremidades de cabos a seremhermeticamente conectadas. O presente dispositivo compreendeum suporte rígido mecanicamente ligado com cada um dos cabos,uma cobertura flexível passada em torno das extremidades doscabos, e uma vedação sobre a qual a cobertura flexível é aplicadae própria para impermeabilizar o dispositivo em torno dasextremidades dos cabos.
Patent BR-9709079-A (BR)
Inventor: CHAUDHURI RATAN K
IPC: A61K8/81
Filed: 1997-01-15
Abstract: A cosmetic composition for rejuvenating the appearance of skin with reduced or minimal potential for skin irritation, in the form of a lotion, creme, solution or gel, includes an aqueous, alcoholic or aqueous-alcoholic solution of a polymer having a carboxylic acid functionality, the solution having a pH of 1.5 to 5.